FLOW CONTROLLER FOR CARBONATED BEVERAGES

Abstract: A beverage flow controller includes a tube (16) having a first end and a second end, and a length between the first end and the second end including multiple constrictions (17, 19). The constrictions (17, 19) have a center to center spacing of at least 4.5 times the diameter of the tube (16) and have an inside diameter of 0.6 to 0.8 times the inside diameter of the tube (16). The constrictions (17, 19) control the flow and provides a pressure gradient along the length of the tube (16).

Description: Description FLOW CONTROLLER FOR CARBONATED BEVERAGES Technical Field This invention relates to a flow controller for carbonated beverages and, in particular, to a flow control¬ ler for minimizing outgassing of the beverage as dispensed and of the beverage remaining in a bottle. Background Art A carbonated beverage from a bottling company contains a significant amount of carbon dioxide dissolved in water, the two basic ingredients of all carbonated soft drinks. A large amount of carbon dioxide is dissolved in the soft drink to insure a minimal effervescence after the beverage is poured into a glass. Dispensing a carbonated beverage causes a significant loss of carbon dioxide which usually manifests itself as foaming. "Clear" or non-cola beverages foam less than cola beverages and root beer is formulated to sustain a foam. Foaming and loss of carbonation are related as quantity and quality, not as alternative descriptions of the same problem. Foaming relates to how quickly a beverage can be delivered to a glass or other container. If a great deal of foam is produced, the volume of beverage delivered is relatively low and it takes a long time to fill a glass because of the time it takes for the foam to dissipate. An alternative is to fill the glass while letting the foam spill into a drain, wasting the beverage. Loss of carbonation occurs in the beverage dispensed and in the beverage remaining in the bottle. In either case, the beverage goes "flat" and the taste is less appealing to most people. Actually, the reduced efferves¬ cence weakens the aroma of the beverage, which is inter¬ preted as a loss of taste or flavor. Regardless of what is actually happening, the beverage industry relies on what consumers perceive and the perception is that the beverage has lost its flavor. With the popularity of the two liter "PET" (poly-eth- yleneterephthalate) bottle, it is essential for good flavor that the beverage in a partially emptied bottle not go flat. The bottling industry addresses the problem by dissolving a large quantity of carbon dioxide in the beverage, creating an unstable, super-saturated solution. Opening a bottle and pouring a drink reduces the effervescence of the beverage in two ways. Opening or unsealing the bottle releases the C0 2 which has escaped from the beverage during storage. The act of pouring disturbs the beverage, causing the release of the dissolved carbon dioxide from both the beverage being dispensed and the beverage remaining in bottle. Once carbon dioxide is released, it does not re-dissolve. By dissolving a large amount of carbon dioxide in the beverage, the bottlers are attempting to assure that some will remain dissolved when the last of the bottle is poured. The prior art has addressed the problem of loss of carbonation with a variety of dispensers. U.S. Patent 3,976,221 (Martin et al.) discloses a dispenser which uses a C0 2 cartridge but adds a foam inhibiting portion includ¬ ing a passageway having two constrictions in the form of Teflon balls of different sizes in the passageway. U.S. Patent 5,022,565 (Sturman et al.) discloses a dispenser which uses a C0 2 cartridge and a pressure regulator to maintain pressure within a bottle and to prevent efferves¬ cence within the bottle. The Sturman et al. patent also discloses that "the use of some form of flow restrictor ... will only aggravate the foaming problem." Neither patent addresses the problem of providing an optimum flow of beverage to minimize the time for filling a glass or other container. Corrugated tubes for beverages are known in the art, e.g. a straw having a corrugated section, but only for flexibility, not for controlling the flow of carbonated beverage. Disclosure of the Invention The essential features of the invention include a flow controller having a first end and a second end, and a length between said first end and said second end including at least three constrictions in which the cross-sectional area of the tube is reduced. In one embodiment of the invention, the constrictions are sections of the tube having a reduced diameter, wherein the constrictions have a center to center spacing of at least 4.5 times the inside diameter of the tube and have an inside diameter of 0.6 to 0.8 times the inside diameter of the tube. In an alternative embodiment of the invention, the tube includes an insert having portions of larger or smaller diameter to reduce the cross-sectional area of the tube. The larger outside diameter of the insert is less than the inside diameter of the tube and the insert is held in place by longitudinal webs engaging the inside of the tube. The cross-sectional area of the flow space (between the larger diameter portion of the insert and the inner wall of the tube) is 0.36 to 0.64 times the cross-sectional area of the flow space at the smaller diameter portion of the insert. The constrictions control the flow and provide a pressure gradient along the length of the tube for reducing foaming while providing a high volume of beverage. Accordingly, the beverage dispenser of the present invention is capable of quickly delivering a large volume of carbonated beverage with only a minimal amount of foaming and minimal outgassing of carbonation from the dispensed beverage. The improved controller of the invention can be added to externally charged dispensers, or it can be sealed to a bottle for dispensing carbonated beverage by means of accumulated pressure in the bottle. Brief Description of the Drawings A more complete understanding of the invention can be obtained by considering the following detailed description in conjunction with the accompanying drawings, in which: FIG. 1 illustrates a bottle including a flow control¬ ler constructed in accordance with a preferred embodiment of the invention; FIG. 2 is a detail of a section of tubing having constrictions in accordance with the invention; FIG. 3 is a diagram of the geometry of a flow control constructed in accordance with the invention; FIG. 4 is a chart comparing the amount of foaming of a typical cola with the number of constrictions for different ratios of constriction diameter to tube diameter; FIG. 5 is a chart comparing the residual pressure in dispensed beverage with the number of flow sections; FIG. 6 is a chart comparing the time to dispense a predetermined amount of beverage with the number of flow sections; and FIG. 7 illustrates a flow control constructed in accordance with an alternative embodiment of the invention. Best Mode for Carrying Out the Invention In the description which follows, like parts are indicated throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details of the invention. As used herein, "bottle" designates the source of a beverage, whether the source is actually a bottle or is a can, keg, or some other container. "Bottle" does not imply a particular material since carbonated beverages come in containers made from metal, plastic, glass, or other materials. In FIG. 1, bottle 11 includes threaded neck 12 for engaging cap 14 to close the bottle. Cap 14 includes a suitable valve and spout (not shown) for dispensing the beverage from bottle 11. Interposed between cap 14 and the beverage within bottle 11 is a flow controller for convey- ing the beverage to cap 14. The flow controller includes tube 16 and a plurality of constrictions such as constric¬ tions 17 and 19. Tube 16 is held in place by gasket 21 which seals the bottle to retain the gas bubbling out of the beverage. As the gas escapes, pressure builds up within the sealed bottle and this pressure is used to propel the beverage through the flow controller and from the bottle when the valve (not shown) in cap 14 is opened. Tube 16 is illustrated in greater detail in FIG. 2 which illustrates a flow control section constructed in accordance with the invention. Tube 16 can be made from any rigid or flexible material in which the constrictions are permanently formed into the tubing or are temporarily produced by external rings, such as rings 25 and 27, held in place by friction or a suitable adhesive. In a pre- ferred embodiment of the invention, tubing 16 is made from a thermosetting plastic in which the constrictions are permanently formed in the tubing. A flow control section includes two constrictions separated by a predetermined distance. In addition to the diameter of the constriction, the length of the constric¬ tion along the longitudinal axis of the tube contributes to the control of the flow of beverage through the tube. In FIG. 2, the length of the constriction is denoted LI, the transition from the constriction to the full diameter of the tube is denoted by length L2, and the distance between constrictions is denoted L3. There are two aspects to the problem of dispensing carbonated beverages, one is quantity and the other is quality. Pouring from an opened bottle obviously provides the maximum quantity of beverage but the turbulent and chaotic flow of the beverage, and the velocity with which it strikes the glass or other container, can cause exces- sive foaming and outgassing. Pouring very slowly increases the time it takes to fill a glass and does not overcome the problem of releasing accumulated C0 2 each time the bottle is opened. It has been found that simply providing a tube of a particular diameter does not permit one to dispense the maximum amount of beverage in the least amount of time with minimal outgassing. In accordance with the invention, multiple constrictions are provided in a tube to control the flow and to control the pressure drop or pressure gradient between the pressure within a bottle and the pressure outside the bottle, i.e. ambient or atmospheric pressure. The particular geometry described herein relates to dispensing carbonated beverages having a temperature of 30° to 50° Fahrenheit (about -1° Celsius to 10° Celsius) and a pressure in the bottle of approximately 10-40 pounds per square inch (psi) (about 0.70 Kg per sq. cm to 2.8 Kgs per sq. cm) above ambient pressure. Pressure and tempera- ture are related but not linearly. The temperature range given is the typical serving temperature for beverages. At higher temperatures, the outgassing is more severe and the pressure is higher. As more fully described herein, the pressure affects the preferred number of constrictions. FIG. 3 illustrates the geometry of a constriction in accordance with the invention. The number of constrictions and the geometry of the constrictions controls the flow of beverage. It is believed that the invention works by distributing the pressure gradient (between the bottle and ambient or atmospheric pressure) over the length of the tube (i.e. over the distance between the beginning of the first constriction and the end of the last constriction) , thereby preventing a flow sufficiently turbulent to cause significant outgassing of the beverage. At the same time, the quantity of beverage flowing through the tube is as high as possible but at a sufficiently low velocity that the beverage does not outgas significantly upon striking a glass. The geometry of the constriction illustrated in FIG. 3 is summarized in the following table in which Dl is the inside diameter of the tube, D2 is the inside diameter of the constriction, and LI, L2, and L3 are as defined above. 0.2 inch (0.5 cm) > Dl > 0.1 inch (0.25 cm) 0.8 X Dl > D2 > 0.6 X Dl 2 X Dl > LI > Dl 1.5 x Dl > L2 > 0.5 X Dl 8 X Dl > L3 > 3 X Dl The constrictions have a center to center spacing of L1+L2+L3 or from 4.5 to 11.5 times the inside diameter of the tube. FIG. 4 illustrates the relationship between the number of flow sections and the amount of foaming. It has been found that a minimum number of flow sections is required and that the maximum number of flow sections is determined by the size of the pressure gradient. A higher number of flow sections is preferred for higher pressure gradients to keep the pressure drop per flow section approximately one to four psi (about 0.1 Kg per sq. cm to about 0.3 Kg per sq. cm) . As illustrated in FIG. 4, two constrictions and the distance between them, i.e. one flow section, is not sufficient to reduce excessive foaming, indicated on abscissa 31 in FIG. 4. The scale on abscissa 31 is a subjective rating of foaming. The amount of foaming depends upon the kind of beverage being tested. As described above, clear beverages have the least foaming while colas and root beer has the greatest foaming. For a dark cola, it has been found that five to eight constric¬ tions (four to seven flow sections) reduces the foaming to -lo¬ an acceptable level while providing the maximum amount of beverage per unit time. For colas stored at 15-31 psi (about 1 Kg per sq. cm to about 2 Kg per sq. cm) , eight to twelve restrictions are preferred. FIG. 4 also illustrates the effect of the ratio of the inside diameter of the constriction to the inside diameter of the tube on foaming. It has been found that a ratio of 0.69 produces the greatest effect within a range of 0.6 to 0.8. FIG. 5 illustrates the residual pressure of C0 2 in dispensed beverage compared to the number of flow sections used to dispense the beverage. The residual pressure of C0 2 in the dispensed beverage was determined by dispensing eight ounces of beverage into a sample bottle and then immediately sealing the sample bottle. The sample bottle was then shaken vigorously to drive the residual C0 2 out of the beverage. The bottle was then immersed in a 40°F (about 4 degrees Celsius) bath for a minimum of one minute and the pressure was measured by a pressure gauge attached to the sample bottle. The higher the pressure, the greater the effervescence level of the dispensed beverage. If the pressure was seven psi (about 5 Kg per sq. cm) or less, the dispensed beverage was considered "flat." The test was repeated for flow controllers having different numbers of constrictions. As shown in FIG. 5, the residual pressure, which indicates the amount of carbonation remaining in the beverage, increased signifi¬ cantly with five to ten flow control sections. As part of the test, the time required for the liquid (not liquid plus foam) to reach the eight ounce (0.24 liter) mark was measured. As shown in FIG. 6, the time to dispense eight ounces (0.24 liter) of beverage decreases significantly using a flow controller constructed in accordance with the invention. Particularly with five to ten flow control sections, the time to fill an eight ounce (0.24 liter) glass decreases from approximately two hundred forty seconds to approximately eighteen seconds. These times are for a single tube having a plurality of flow control sections. Obviously, the filling time can be further reduced by using two or more tubes in parallel, e.g. two tubes would double the flow. A flow controller constructed in accordance with the invention divides the pressure gradient between the bottle and atmospheric or ambient pressure to reduce the turbu¬ lence of the flow and the consequent outgassing. The transition (L2) from the full diameter of the tube to the constriction is believed to reduce eddy currents which could cause outgassing, greatly changing the local pressure in the tube. FIG. 7 illustrates a flow controller in which the tube has a uniform inside diameter and contains an insert for changing the flow space, i.e. the cross-sectional area through which the beverage can flow. In FIG. 7, the flow controller includes tube 41 and insert 43. Insert 43 has a plurality of sections, such as sections 45 and 46, having a larger diameter and sections having a smaller diameter, such as section 47, connected by smooth transitions. Insert 43 can be held in place at each end or by longitudi¬ nal webs along the length of the insert, such as webs 52 and 53. Webs 52 and 53 can extend the length of insert 43 or can be segmented as shown in FIG. 7. The dimensions LI, L2, and L3, described above, apply to insert 43. The ratios described above in terms of diameter apply to insert 43 but are expressed in terms of cross-sectional area. Defining the flow space around section 47 as Al and the constriction or flow space around section 45 as A2, then the following table shows the relationship of the areas: 0.031 inch (0.2 sq. cm) > Al > 0.008 inch (0.05 sq. cm) 0.64 Al > A2 > 0.36 Al 0.4 inch (1 cm) > LI > 0.1 inch (0.25 cm) 0.3 inch (0.7 cm) > L2 > 0.05 inch (0.13 cm) 1.6 inch (4 cm) > L3 > 0.3 inch (0.76 cm) The invention thus provides a flow controller for carbonated beverages which provides a large flow of beverage with a minimum amount of foaming and a maximum amount of effervescence in the dispensed beverage. The flow controller can be added to existing dispensers and made an integral part of new dispensers. The flow control¬ ler is sealed to the bottle to prevent loss of escaped gas and to retain as much gas as possible in the beverage remaining in the bottle. -13- Industrial Applicability It will be apparent to those skilled in the art that various modifications can be made to accommodate industri¬ al, commercial and domestic applications. For example, the flow controller can be adapted for home use by including a manual pump or a C0 2 cartridge for propelling the beverage from bottle 11. The particular geometry will change for other applications of the invention, e.g. for filling the bottles at a bottling plant in which the beverage is at a temperature less than 38° Fahrenheit (about 3° Celsius) in order to increase the solubility of the C0 2 . In particu¬ lar, the inside diameter of the tube can be larger for beverages at lower temperatures. The ratios remain approximately the same. One or more tubes constructed in accordance with the invention can be used for conveying carbonated beverages from any source at one pressure to a destination at another pressure, e.g. for filling or dispensing from beer kegs in a tavern or restaurant. While illustrated as a tube having a circular cross- section, the flow controller tube can have any desired cross-section although curves are preferred to figures having corners. The maximum separation (L3) of the constrictions is largely dependent upon the overall available length for the flow controller. For a two liter bottle, the overall length available for the flow control¬ ler is less than twelve inches (about 30 cm) . Connecting a beer keg to a tap with a flow controller constructed in accordance with the invention, L3 can be larger than the maximum dimension given above. Beyond the minimum separa¬ tion described above, one can separate the constrictions by any desired amount, although this might make the flow controller unnecessarily long.

Claims: Claims 1. A beverage dispenser characterized by: a bottle for containing a beverage; a cap attached to the bottle for sealing the bottle, the cap containing a valve for controlling the flow of beverage from the bottle; and a tube having a first end connected to the cap and a second end in the bottle for conveying the beverage to the cap, the tube having an inside diameter and a length between the first end and the second end including at least three constrictions, wherein the constrictions have a center to center spacing of from 4.5 to 11.5 times the inside diameter of the tube. 2. The dispenser as set forth in claim 1 character- ized in that the constrictions have an inside diameter of 0.6 to 0.8 times the inside diameter of the tube. 3. The dispenser as set forth in claim 2 character¬ ized in that the constrictions have an inside diameter of 0.69 times the inside diameter of the tube. 4. The dispenser as set forth in claim 1, claim 2 or claim 3 characterized in that the tube includes at least five to ten constrictions. 5. The dispenser as set forth in claim 1, claim 2 or claim 3 characterized in that the tube includes at least eight to twelve constrictions. 6. The dispenser as set forth in claim 1, claim 2 or claim 3 characterized in that each constriction has a length of 1 to 2 times the inside diameter of said tube. 7. The dispenser as set forth in claim 1, claim 2 or claim 3 characterized in that the tube has an inside diameter Dl, each constriction has an inside diameter D2 and a length LI, and a distance L3 between constrictions not including a transition length L2, wherein 0.8 X Dl > D2 > 0.6 X Dl 2 x Dl > LI > Dl 1.5 X Dl > L2 > 0.5 x Dl 8 x Dl > L3 > 3 X Dl. 8. A flow controller for conveying carbonated beverage from a source at a first pressure to a destination at a second pressure, the flow controller characterized by: a tube having a first end, a second end, and a length between the first end and the second end, the tube having an inside diameter and at least three constrictions disposed along its length, wherein the constrictions have a center to center spacing of from 4.5 to 11.5 times the inside diameter of the tube. 9. The flow controller as set forth in claim 8 characterized in that the constrictions have an inside diameter of 0.6 to 0.8 times the inside diameter of the tube. 10. The flow controller as set forth in claim 8 characterized in that the tube includes at least five to ten constrictions. 11. The flow controller as set forth in claim 8 characterized in that the tube includes at least eight to twelve constrictions. 12. The flow controller as set forth in claim 8 characterized in that each constriction has a length of 1 to 2 times the inside diameter of the tube. 13. The flow controller as set forth in claim 8 characterized in that the tube has an inside diameter Dl, each constriction has an inside diameter D2 and a length LI, a distance L3 between constrictions not including a transition length L2, wherein 0.8 X Dl > D2 > 0.6 x Dl 2 x Dl > LI > Dl 1.5 X Dl > L2 > 0.5 x Dl 8 X Dl > L3 > 3 X Dl. 14. A dispenser for a carbonated beverage, the dispenser characterized by: a bottle for containing a carbonated beverage; a cap attached to the bottle for sealing the bottle, the cap containing a valve for controlling the flow of beverage from the bottle; a tube having a first end connected to the cap and a second end in the bottle for conveying the beverage to the cap, the tube having an inside diameter and a length between the first end and the second end; and an insert disposed in the tube, the insert having a plurality of first sections having a first diameter separated by a plurality of sections having a second diameter, wherein the first diameter is greater than the second diameter and the sections form at least three constrictions along the length and the flow space through each constriction is from .36 to .64 times the flow space between constrictions.

Inventors: NELSON PETER KENNARD, QUERIN BRIAN DAVID, NELSON, PETER, KENNARD, QUERIN, BRIAN, DAVID
Applicants: NELSON PETER KENNARD, QUERIN BRIAN DAVID, NELSON, PETER, KENNARD, QUERIN, BRIAN, DAVID
Application year: 1994
Main classification: B67D5
IPC codes: B67D1